Pen



FIG. 1 is a perspective view of the pen showing my new design;

FIG. 2 is a front view thereof.

FIG. 3 is a bottom view thereof.

FIG. 4 is a rear view thereof.

FIG. 5 is a side view thereof; and,

FIG. 6 is a top view thereof. 

The ornamental design for a pen, as shown and described. 